Mehanizmi izjemne odpornosti proti radioaktivnemu sevanju pri prokariontih

Introduction Extremophiles are organism that live, metabolize and reproduce to human extreme conditions. We define a variety of extreme conditions such as high or low temperatures, pH, salinity, pressure and radiation. Scientists find this organisms extraordinary, especially their metabolism, mechanisms of DNA repair and protein antioxidants. The most impressive extremophile organisms are those resistant to high levels of ionizing radiation. Bacterium Deinococcus radiodurans can survive exposures as high as 15 kGy (Gray is an SI unit for absorbed radiation dose), while for humans a lethal dose is around 10 Gy and average bacterium around 200 Gy. Ionizing radiation causes severe damage on living cells such as formation of ROS, DNA single and double strand brakes, DNA extensive base modifications. Evidently some bacterium have mechanism that fight radiation damage. Due to lack of radioprotectors this bacterium ability rises high interest as a potential suppressor of radiation effects. Suppressing side effect on healthy cells in cancer radiations treatments would have enormous benefit as higher radiation doses would be allowed with better anticancer effect.